To make economic sense, each aircraft needs to do at least 350 - 400 hours per year, in fact you shouldn't look at acquiring a second aircraft until you're looking at 350 hours on the first. The only way of getting up to those sorts of hours is to operate ab initio training with Trail Lesson sales. That means starting as an ATO, with all the paperwork etc and probably paid staff.
It also means sensibly, a 4-seater, to lift enough load for the +16 stone that many folk seem to be these days (and the blokes are even more!!). Finding either a PA28 or a C172 with an engine in calendar and clock hours that's presentable enough is going to be somewhere well in excess of £40k at the moment.
Sooo, if you're thinking C150 or 152, then for heavens sake look at Ikarus C42. MUCH cheaper to operate with similar mission profile. No hassle with having to set up an ATO for ab initio, though you might struggle to find one that's legal to rent out and an instructor who isn't already working elsewhere.
TOO